The goal of this research is to determine the neural basis of aggressive behavior, first in cats, ultimately in monkeys, with a view to clarifying the neural basis of aggressive behavior in man. We propose to observe naturally occurring aggressive behavior in cats with a view to determining the forms its takes, and to secure experimental control over its occurrence. We use aggressive behavior elicited by electrical stimulation of the brain to help us determine the mechanisms, and anatomical and physiological techniques to identify them. This knowledge will serve as the basis for the investigation of the aggressive behavior that occurs naturally.